diff --git a/include/posix/io_posix.h b/include/posix/io_posix.h
index aaa6b4048..65645b0ff 100644
--- a/include/posix/io_posix.h
+++ b/include/posix/io_posix.h
@@ -6,6 +6,7 @@
 // Copyright (c) 2011 The LevelDB Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file. See the AUTHORS file for names of contributors.
+#pragma once
 #include <deque>
 #include <set>
 #include <dirent.h>